1. Field of the Invention
The invention relates to an improved pass-through vacuum and vacuum system, wherein a multiplicity of supersonic jets of compressed gas are utilized to increase their performance and to the unique construction of the vacuum which increases the flexibility of their use.
2. Description of Related Art
Systems that blow compressed air along the inside of a pipe or tube to create a simple vacuum are well known. Suction is created at the entrance of the tube suitable for entraining a solid or liquid material. On the discharge end of the tube, a hose may be connected for directing the material safely to a desired location. An extension hose or tube may be attached to the inlet section of the tube to increase the reach of the unit.
Being light in weight, low in cost, vibration free, and powered by a readily available portable air compressor, a pass-through vacuum offers advantages over standard, industrial vacuum units or trucks using a roots blower or centrifugal fan.
However, many prior art systems have disadvantages as well. In the simplest construction, the air pipe itself may block part of the vacuum tube limiting the size of material that may be conveyed. Inefficient means may also be used to convert the energy of the input compressed air into vacuum head to move the material. Such is the case, for example, for vacuum models which use simple sharp, edged holes as acceleration nozzles. Many compressed air amplifiers are also commercially marketed. However, these generally are for moving high volumes of air and, as such, produce low heads not suitable for moving difficult to convey materials like excavated soil.
Further, prior art systems utilize a single-piece injection unit for both the injection of compressed gas into the system and the conveyance of material through the system. This causes a great deal of wear on the injection unit since flowable material conveyed through the injection unit by the entrained gas flow will continually pit and scratch the interior of the injection unit during use. Consequently, the injector units do not have a particularly long service life in comparison to their relatively high cost. Further, prior art injection units do not have the capability of selecting the number of nozzles that inject compressed gas into the system. Thus, individual injector units may not be suitable for use with a large variety of compressors or in many different projects.